Factors that affect the mean size of Chilean hake (Merluccius gayi gayi) caught with gillnets in 2001-2018 in central Chile

Abstract

Chilean hake (Merluccius gayi gayi) is one of central Chile's most important demersal resources, and its fishery involves an artisanal fleet that mainly uses gillnets. In the recent history of the fishery, there has been a decrease in catch sizes and a progressive reduction in mesh sizes. This study aimed to analyze the factors that influenced the mean catch sizes of Chilean hake between 2001 and 2018 to understand this situation, correlating the response of fishermen with the capture efficiency of the nets used. Applying a generalized linear model, a significant effect of the factors year, port (zone), and mesh size were observed on the mean size of individuals caught. The model explained 85% of the deviation, the greatest relative contributions being made by the factors year (53.6%) and port (30.2%). A lower effect was estimated for the mesh size factor with 1.2% deviance. These findings suggest that the progressive reduction in mesh sizes is associated with a response to the demographic change in the stock. Differentiated management measures by zones could be considered in the fishery, given the estimated differences.